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[apdl] HOW TO USE CREATED ETABLEs IN /SOLUTION
 
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debabrata.podder
User


Joined: 21 Feb 2013
Posts: 51
Location: NIT Meghalaya, India

PostPosted: Tue Aug 27, 2013 4:45 pm  Reply with quote

Dear experts,
I have made ETABLEs like this :
/post1
*DO,K,1,LOOPPAR+42,1
SET,K,LAST
ETABLE,ETA%K%,TEMP
*ENDDO
K=K+1
FISISH
And I am going to utilize these ETABLEs in /SOLUTION like this:
/SOL
.....
...
i=1
*DO,T,51,LOOPPAR+42,1
TIME,DEL_T*T
!NSUBST,26,1000,2
NSUBST,6,6,6
!NEQIT,35
LDREAD,TEMP,,,DEL_T*T,0,PLATE_WELD_THERMAL,RTH
ESEL,S,ETAB,ETA %i%,1000
EKILL,ALL
MPCHG,2,ALL
ALLSEL,ALL
SOLVE
EALIVE,ALL
*ENDDO
i=i+1

But what I am observing that, after running the analysis this technique is not serving my purpose !! Actually I am doing a welding analysis, where I have adopted element birth and death method. So in structural analysis, I want to select elements which have temperatures greater than 1000 deg C and want to kill them. But after applying this method of ETABLE an error is coming like : 'Some elements are getting highly distorted ...!!!'. Am I correctly implementing the ETABLE technique !!! Please share some idea. Thanks in advance.

Regards-
_________________
Debabrata Podder(PhD)
Assistant Professor
NIT Meghalaya
India
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danbohlen
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Joined: 18 Aug 2008
Posts: 951
Location: Evendale OH

PostPosted: Wed Aug 28, 2013 4:00 am  Reply with quote

Just a guess, but I doubt "ETABLE" is the cause of the problem....


Dan Bohlen
Senior/ SSt Engineer, Military HPT Analysis
STAR review chairman, Fan and Booster
GE Aircraft Engines
1 Neumann Way
Evendale, OH 45215
Build 90 Col K1.5 cube 1N152
M/D H110 513-243-2366
Dial Comm *332-2366




-----Original Message-----
From: xansys-bounces@xansys.org [mailto:xansys-bounces@xansys.org] On Behalf Of debabrata.podder
Sent: Tuesday, August 27, 2013 7:45 PM
To: xansys@xansys.org
Subject: [Xansys] [apdl] HOW TO USE CREATED ETABLEs IN /SOLUTION

Dear experts,
I have made ETABLEs like this :
/post1
*DO,K,1,LOOPPAR+42,1
SET,K,LAST
ETABLE,ETA%K%,TEMP
*ENDDO
K=K+1
FISISH
And I am going to utilize these ETABLEs in /SOLUTION like this:
/SOL
.....
...
i=1
*DO,T,51,LOOPPAR+42,1
TIME,DEL_T*T
!NSUBST,26,1000,2
NSUBST,6,6,6
!NEQIT,35
LDREAD,TEMP,,,DEL_T*T,0,PLATE_WELD_THERMAL,RTH
ESEL,S,ETAB,ETA %i%,1000
EKILL,ALL
MPCHG,2,ALL
ALLSEL,ALL
SOLVE
EALIVE,ALL
*ENDDO
i=i+1

But what I am observing that, after running the analysis this technique is not serving my purpose !! Actually I am doing a welding analysis, where I have adopted element birth and death method. So in structural analysis, I want to select elements which have temperatures greater than 1000 deg C and want to kill them. But after applying this method of ETABLE an error is coming like : 'Some elements are getting highly distorted ...!!!'. Am I correctly implementing the ETABLE technique !!! Please share some idea. Thanks in advance.

Regards-

------------------------
Debabrata Podder
Research Scholar
IIT Kharagpur
PIN NO.: 721302
India






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Dan Bohlen
Senior Staff Engineer
GE Aircraft Engines
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christopher.wright
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Joined: 17 Jun 2009
Posts: 927

PostPosted: Wed Aug 28, 2013 11:07 am  Reply with quote

On Aug 28, 2013, at 6:00 AM, Bohlen, Dan (GE Aviation, US) wrote:

Quote:
Just a guess, but I doubt "ETABLE" is the cause of the problem....

Me, too. I've about fisished worrying about it.

Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw@skypoint.com | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/members/chrisw/

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debabrata.podder
User


Joined: 21 Feb 2013
Posts: 51
Location: NIT Meghalaya, India

PostPosted: Wed Aug 28, 2013 10:25 pm  Reply with quote

Dear Dan & Chris,

Your guess is right. Actually I don't need to define any ETABLE for welding analysis. As temperature dependent materials properties are provided, it will automatically define the material properties according to various temperatures. One have to just call the thermal load by LDREAD command.

One more thing I want to ask:
Will the result vary according to the methods of load applied ?
Like if I use the option KBC,1 instead of KBC,0 or vise-verse ?? Because in welding I guess, the loading is step loading (KBC,1) not ramped loading (KBC,0). But in most of the cases convergence problem occurs if one uses the option KBC,1 !!! So recently I have shifted to KBC,0 and I am getting full convergence.

Regards-
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Debabrata Podder(PhD)
Assistant Professor
NIT Meghalaya
India
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jerzy.cwifeld
User


Joined: 02 May 2013
Posts: 39

PostPosted: Thu Aug 29, 2013 4:40 am  Reply with quote

Hi Debabrata,
KBC,1 is never a physically correct. KBC,1 can be used when the load changes much faster that the time step used in analysis.

Regards
Jerzy
+46 73 7305104
-----Ursprungligt meddelande-----
Från: xansys-bounces@xansys.org [mailto:xansys-bounces@xansys.org] För debabrata.podder
Skickat: den 29 augusti 2013 07:26
Till: xansys@xansys.org
Ämne: Re: [Xansys] [apdl] HOW TO USE CREATED ETABLEs IN /SOLUTION

Dear Dan & Chris,

Your guess is right. Actually I don't need to define any ETABLE for welding analysis. As temperature dependent materials properties are provided, it will automatically define the material properties according to various temperatures. One have to just call the thermal load by LDREAD command.

One more thing I want to ask:
Will the result vary according to the methods of load applied ?
Like if I use the option KBC,1 instead of KBC,0 or vise-verse ?? Because in welding I guess, the loading is step loading (KBC,1) not ramped loading (KBC,0). But in most of the cases convergence problem occurs if one uses the option KBC,1 !!! So recently I have shifted to KBC,0 and I am getting full convergence.

Regards-

------------------------
Debabrata Podder
Research Scholar
IIT Kharagpur
PIN NO.: 721302
India






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| Send administrative requests to xansys-mod@tynecomp.co.uk |
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debabrata.podder
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Joined: 21 Feb 2013
Posts: 51
Location: NIT Meghalaya, India

PostPosted: Thu Aug 29, 2013 12:19 pm  Reply with quote

Dear jerzy thanks.

Regards-
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Debabrata Podder(PhD)
Assistant Professor
NIT Meghalaya
India
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